So guys Ive stumbled into a problem with my vl now I already did a search but couldnt find what I was looking for anyway, its an 87 executive, now the other day i pulled my rocker cover off, i removed all the vacume/ coolant/ oil lines that run to the top of the rocker cover and the plenum. I also removed the throttle body and spark plug leads just to make it easier to get off. The reason i pulled it off was to spray it, now that it had been sprayed the seal has gone hard so I replaced that with a brand new one, anyway after putting it all back together every seal and every nut and bolt, sensor, hose eveything. The car now has a loud backfire, it will rev as far as you push it but wont stop backfiring. Now I checked everything from afm, leads, plugs, dizzy... The only thing that sort of stopped it was changing the o2 sensor in the exhuast with one from my mates vlt, it was idling fine with no backfiring when reving, but whenE I try to take it for a drive to see if its fixed the problem it just kept backfiring with only a little bit of load on the engine? And it makes no sense because the car was running fine before i pulled the rocker cover off. Anyways guys/ girls if you have any input or solution to my problem it would be greatly appreciated.

Seems like injector issue or wiring loom happened to me after changing everything under the bonnet turns out the one of the injectors were not spraying right

Quote: Originally Posted by ibbi [View Post] Seems like injector issue or wiring loom happened to me after changing everything under the bonnet turns out the one of the injectors were not spraying right So to check them I should unplug each injector, if it stays the same the that injector will be faulty? if it drops in revs or continues backfiring then its not the injectors right?

Hard to say dude mine backfired when hit boost I tried that there is a proper way to test them like I was sayin they were fireing but weren't spraying right so might need to take them off completely test one at a time you can easily do ur without takin off the plenum my opinion is to try a mates fuel rail and go round the loom checking for any cracks or bare wire that might be earthing also check that ur tps is workin fine let me no how u go coz I no how frustrating it is

Anyone got anymore ideas? I really cant think of what it could be, really want to get the car running.. looks like its off to the mechanic :/

Double check your clips to all connections. You might have knocked the plug to the oxygen sensor. Check your leads from the distributor to spark plugs are in the right firing order. If you have a standard ecu do a diagnostic check.

Would pulling the bottom and top parts of the timing cover off affect anything? maybe the timing change when I pulled it off? Is this a possibility?

No it wouldn't. Where is your coil located??

Quote: Originally Posted by HTURBO [View Post] No it wouldn't. Where is your coil located?? Just in the standard spot? your talking about the ignition coil right?

Simple stuff first, check to make sure all the leads from the plugs to dizzy are in the right spot.

maybe CAS connection, they can be tempermental.

Hmm might have to check out that, could the connection be dodgy and making it backfire?

Could it be the afm? I resealed/ tightened all the intake hoses and it seems to idle a lot smoother but still backfiring. Im think the afm could be making it run rich i.e. adjusting the fuel and making it run rich because its faulty??

got the leads back in the right firing order? wrong firing order will cause backfiring! and when do you say "backfire" is it actually making a loud bang or is it misfiring?

Check the connections to the injectors again. it is possible to use the IACV connector on one of the injectors. if you did the injector will be on all the time literally trying to flood the cylinder. pop out the spark plugs starting at the front to see which one has been drowned in fuel.

Quote: Originally Posted by dirty30et [View Post] got the leads back in the right firing order? wrong firing order will cause backfiring! and when do you say "backfire" is it actually making a loud bang or is it misfiring? Its definatly a loud bang... I changed the leads and it seem to be alright, for 2 seconds to get my hopes up, but still backfiring. Smells like its running rich aswell. ---------- Post added 16-08-12 at 22:26 ---------- Quote: Originally Posted by bachig24u [View Post] Check the connections to the injectors again. it is possible to use the IACV connector on one of the injectors. if you did the injector will be on all the time literally trying to flood the cylinder. pop out the spark plugs starting at the front to see which one has been drowned in fuel. how can I tell if its been flooded? I never unplugged any of the injectors, So would that still be a possibility?

Sounds like your AFM. TO TEST AFM: pull back the rubber boot on the AFM connector revealing the wires. grab your multimeter and stick the probes on wire 4 (white) and 3 (1 being the closest to the airbox) with the multimeter on DC voltage. turn the ignition on and the voltage reading should be between 1.26V (lean) and 1.32V (rich). this is the base setting and if it is out then the AFM wont be able to be adjusted to a satisfactory mixture (meaning you need a new one) and just for interests sake you can test the mixture by putting the probes on wire 1 and 3 with the key on and measuring the voltage. 3.6V is the factory setting which is lean, with 2.0V being rich. the mixture should be in the vacinity of 2.0-4.0i couldn't get the LED's to flash and therefore couldn't set it using the computer so i did it this way and set it to 3.5V (AFM resistance of 375 ohms) and then checked it using the computer and it was right, LED's flashing together.

Well I'm going to get a new afm today and see if that is the problem. Im also thinking it could be a connection on the dizzy, it looks a little burnt out..

Sparkplug leads not on the right plug I'm guessing...

Quote: Originally Posted by Duke57TT [View Post] Sparkplug leads not on the right plug I'm guessing... Well I didn't unplug them from the dizzy, only from the plugs, and they have been checked like 10 times, the car was running perfect before, so I have no idea what is wrong with it... ---------- Post added 17-08-12 at 16:20 ---------- Afm is hopefully going to be chanhed today and Im hoping that it will fix it :/